CN-121983793-A - Three-dimensional metamaterial unit cell unit and three-dimensional heterostructure metamaterial

CN121983793ACN 121983793 ACN121983793 ACN 121983793ACN-121983793-A

Abstract

The invention discloses a three-dimensional metamaterial unit cell and a three-dimensional heterostructure metamaterial. The unit cell cube structure comprises a body center sphere and six groups of connecting rods respectively arranged between six faces of the cube and the body center sphere, wherein each group of connecting rods comprises four curve rods, first ends of the four curve rods are respectively connected to the surface of the body center sphere and are arranged in a quadruple rotation symmetry mode by taking a center normal line of a corresponding cube face as an axis, and second ends of the four curve rods are suspension ends and are used for being connected with adjacent unit cell units when the metamaterial is formed. The three-dimensional heterostructure metamaterial effectively widens the transmission attenuation frequency band of the metamaterial on the premise of not remarkably increasing the structural size and the quality by adopting a cell design mode that the three-dimensional heterostructure metamaterial can be independently adjusted by virtue of a body-centered sphere and six groups of four-curve rods.

Inventors

Yuan Dinghua
ZHENG YAN
XIAO YI
QIN QINGHUA

Assignees

重庆幂天通讯设备制造有限责任公司
深圳北理莫斯科大学
重庆工业职业技术大学

Dates

Publication Date: 20260505
Application Date: 20260127

Claims (9)

1. A three-dimensional metamaterial unit cell, which is characterized by being in a cube structure and comprising a body-centered sphere and six groups of connecting rods respectively arranged between six faces of the cube and the body-centered sphere; Each group of connecting rods comprises four curve rods, first ends of the four curve rods are respectively connected to the surface of the body center sphere, the four curve rods are arranged in a quadruple rotation symmetry mode by taking the center normal line of the corresponding cube surface as an axis, and second ends of the four curve rods are suspension ends and are used for being connected with adjacent unit cells when the metamaterial is formed.
2. The three-dimensional metamaterial unit cell of claim 1, wherein the centerline of the curved bars is a half-period sinusoidal curve.
3. A three-dimensional metamaterial unit cell according to claim 2, wherein the amplitude a of the sinusoid is 0-5 mm.
4. The three-dimensional metamaterial unit cell according to claim 1, wherein the unit cell constant a of the unit cell is 30-50 mm.
5. The three-dimensional metamaterial unit cell according to claim 4, wherein the radius R of the body-centered sphere is 0.30 a-0.45 a.
6. The unit cell of claim 5, wherein a distance d e between the connecting ends of the surface of the body sphere of two adjacent curved bars in the same group of connecting bars is 0.3r to 0.4r, and a distance d t between the free ends of the two adjacent curved bars is 0.6a.
7. The three-dimensional metamaterial unit cell according to claim 1, wherein the cross section of the curved rod is elliptical, the minor axis r h of the elliptical cross section is 0.6-0.9 mm, and the ratio of the major axis r w to the minor axis r h is 1.5-2.5.
8. The three-dimensional heterostructure metamaterial is characterized by comprising three layers of three-dimensional metamaterial unit cell arrays according to any one of claims 1-7, wherein the three layers of three-dimensional metamaterial unit cell arrays are sequentially stacked in the thickness direction, the unit cell units in the same layer have the same geometric parameters, and part of unit cell units in different layers have different geometric parameters.
9. The three-dimensional heterostructure metamaterial according to claim 8, wherein the partial geometry parameters of the unit cells of the different layers include at least one of a body-centered sphere radius R, a cross-sectional elliptical minor axis R h of a curved rod, a sinusoidal amplitude a of the curved rod, and a distance d e between corresponding ends of the same set of curved rods at the body-centered sphere surface.

Description

Three-dimensional metamaterial unit cell unit and three-dimensional heterostructure metamaterial Technical Field The invention relates to the technical field of low-frequency broadband vibration isolation elastic materials, in particular to a three-dimensional metamaterial unit cell and a three-dimensional heterostructure metamaterial. Background The existing elastic metamaterial/phonon crystal structure can form a band gap in a certain frequency band through a periodic unit, so that elastic wave propagation inhibition is realized. Compared with a two-dimensional structure, the three-dimensional structure has the potential of forming band gaps in three directions of space, is suitable for application scenes for simultaneously inhibiting in-plane and out-of-plane vibration, and can reduce the structure density to a certain extent so as to meet the requirement of light weight. However, in engineering applications where space or weight is limited, the three-dimensional elastic metamaterial unit structure still faces the problems that firstly, the three-dimensional elastic metamaterial unit structure is limited by unit size and configuration, a lower band gap initial frequency is difficult to obtain in a practically required low-frequency range, and secondly, a transmission attenuation band is often narrow, and a broadband vibration environment is difficult to cover. In order to widen the attenuation band, the prior art proposes heterogeneous (non-homogeneous) metamaterial structures, and the degree of freedom of design is increased by the inter-layer parameter difference. However, the existing three-dimensional heterogeneous metamaterial is mostly designed by adopting an equal gradient or single-dimension parameter adjustment mode, the flexibility of parameter combination is insufficient, and the number of layers is often required to be increased to obtain effective attenuation, so that the structural size is increased, and the manufacturing complexity is improved. Therefore, how to reduce the band gap starting frequency and widen the attenuation band by optimizing the combination of cell unit topology and interlayer parameters on the premise of ensuring the vibration isolation attenuation performance, and simultaneously reduce the cell size and the layer number to control the structural size and the manufacturing cost is still a technical problem to be solved in the field. Disclosure of Invention In view of the foregoing, it is desirable to provide a three-dimensional metamaterial unit cell and a three-dimensional heterostructure metamaterial. According to the invention, through the three-dimensional heterostructure metamaterial formed by specific unit cells, the lower band gap initial frequency and the wider elastic wave transmission attenuation band are realized under the conditions of fewer layers and smaller unit size, and the structural stability is considered. In a first aspect, the present invention provides a three-dimensional metamaterial unit cell, wherein the unit cell has a cube structure, and comprises a body-centered sphere and six groups of connecting rods respectively arranged between six faces of the cube and the body-centered sphere; Each group of connecting rods comprises four curve rods, first ends of the four curve rods are respectively connected to the surface of the body center sphere, the four curve rods are arranged in a quadruple rotation symmetry mode by taking the center normal line of the corresponding cube surface as an axis, and second ends of the four curve rods are suspension ends and are used for being connected with adjacent unit cells when the metamaterial is formed. Further, the center line of the curve rod is a half-period sine curve. Further, the amplitude A of the sinusoidal curve is 0-5 mm. The curve rod adopts a sine curve form with specific curvature, and the flexible regulation and control of the equivalent mass and the equivalent rigidity of the unit cell are realized through the multi-parameter collaborative design of the size of the body center sphere, the cross section size of the curve rod, the space interval and the like. Further, the unit cell constant a of the unit cell unit is 30-50 mm. Further, the radius R of the body center sphere is 0.30 a-0.45 a. Further, the distance d e between the connecting ends of the surface of the body center sphere of two adjacent curve rods in the same group of connecting rods is 0.3-0.4 r, and the distance d t between the suspension ends of the two adjacent curve rods is 0.6a. Further, the cross section of the curve rod is elliptical, a minor axis r h of the elliptical cross section is 0.6-0.9 mm, and the ratio of the minor axis r w to the minor axis r h is 1.5-2.5. In a second aspect, a three-dimensional heterostructure metamaterial is formed by sequentially stacking three layers of three-dimensional metamaterial unit cell arrays as described above in a thickness direction. Further, the cell geometry parameters are the same